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added edits for applciatio specific routes on OpenShift cluster
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@VeerMuchandi
VeerMuchandi committed Oct 18, 2018
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162 changes: 122 additions & 40 deletions DeployingSampleApplication.md
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Expand Up @@ -12,7 +12,7 @@ LICENSE bin istio.VERSION tools
README.md install samples
```

### Install Bookinfo sample application
### Deploy Bookinfo sample application

We will deploy the sample bookinfo application explained in the [istiodocs](https://istio.io/docs/guides/bookinfo.html). The instructions are more or less the same as kubernetes with some slight variations. Hence I have documented the openshift deployment process here.

Expand Down Expand Up @@ -108,80 +108,154 @@ ratings ClusterIP 172.30.119.188 <none> 9080/TCP 30s
reviews ClusterIP 172.30.142.212 <none> 9080/TCP 29s
```

In order to make your application accessible from outside the cluster, an [Istio Gateway](https://istio.io/docs/concepts/traffic-management/#gateways) is required.
### Create a Gateway to access your application

In order to make your application accessible from outside the cluster, an [Istio Gateway](https://istio.io/docs/concepts/traffic-management/#gateways) is required. Let us understand gateway and virtual service configurations

```
$ cat samples/bookinfo/networking/bookinfo-gateway.yaml
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
name: bookinfo-gateway
spec:
selector:
istio: ingressgateway # use istio default controller
servers:
- port:
number: 80
name: http
protocol: HTTP
hosts:
- "*"
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: bookinfo
spec:
hosts:
- "*"
gateways:
- bookinfo-gateway
http:
- match:
- uri:
exact: /productpage
- uri:
exact: /login
- uri:
exact: /logout
- uri:
prefix: /api/v1/products
route:
- destination:
host: productpage
port:
number: 9080
```
**Gateway**: A [Gateway](https://istio.io/docs/reference/config/istio.networking.v1alpha3/#Gateway) configures a load balancer for HTTP/TCP traffic, most commonly operating at the edge of the mesh to enable ingress traffic for an application. The above gateway will direct all the `HTTP` traffic coming on port `80` at istio-ingressgateway to the bookinfo sample application.

* The selector `istio: ingressgateway` pull the traffic coming to istio-ingressgateway service in the `istio-system` project
* The parameter `hosts: "*"` says that any traffic coming to this `bookinfo-gateway` for any hostname will be consumed. If we want our application to cater to specific hostnames, we should list those here instead of using `*`

**VirtualService**: A [VirtualService](https://istio.io/docs/reference/config/istio.networking.v1alpha3/#VirtualService) defines the rules that control how requests for a service are routed within an Istio service mesh. With the above virtualservice configuration:

* `gateways: - bookinfo-gateway` configures it to listens to traffic coming to `bookinfo-gateway` defined earlier
* `host: "*"` caters to any hostnames. If we want specific hostname, we can change this to a specific hostname.
* URI matching allows it to listen to `/productpage` etc.

-----
#### Minishift
To deploy with minishift, since it is not multi-tenant you can just deploy the gateway and a virtual service as shown below:

```
$ kubectl apply -f samples/bookinfo/networking/bookinfo-gateway.yaml
gateway.networking.istio.io/bookinfo-gateway created
virtualservice.networking.istio.io/bookinfo created
```
This creates a gateway and a virtual service.
The virtual service above shows that we can access product page at `/productpage` endpoint. This endpoint is for the Istio ingress i.e.,

* A [Gateway](https://istio.io/docs/reference/config/istio.networking.v1alpha3/#Gateway) configures a load balancer for HTTP/TCP traffic, most commonly operating at the edge of the mesh to enable ingress traffic for an application.
```
$ kubectl get route -n istio-system istio-ingressgateway
NAME HOST/PORT PATH SERVICES PORT TERMINATION WILDCARD
istio-ingressgateway istio-ingressgateway-istio-system.192.168.64.72.nip.io istio-ingressgateway http2 None
```

-----

-----
#### OpenShift
To deploy on a multi-user OpenShift cluster, since you want a separate URL for each application instance,

* A [VirtualService](https://istio.io/docs/reference/config/istio.networking.v1alpha3/#VirtualService) defines the rules that control how requests for a service are routed within an Istio service mesh
**Ask your organizer for the Hostname to assign to your application.**<br>
**Ask your organizer for the Hostname to assign to your application.**<br>
**Ask your organizer for the Hostname to assign to your application.**<br>
**Ask your organizer for the Hostname to assign to your application.**<br>
**Ask your organizer for the Hostname to assign to your application.**<br>

The gateway will direct all the `HTTP` traffic coming on port `80` at istio-ingressgateway to the bookinfo sample application
If you are `user1` you will be allocated a url such as `bookinfo1.istio.apps.devday.ocpcloud.com`. The domain name may vary. Similarly `user2` may get `bookinfo2`.

> **Substitute** the value in the command below before running:
The command below will change assign a specific hostname in place of `*`, before creating gateway and virtual service for your application.

```
$ kubectl get gateway
NAME CREATED AT
bookinfo-gateway 11s
sed "s/*/bookinfo1.istio.apps.devday.ocpcloud.com/" samples/bookinfo/networking/bookinfo-gateway.yaml | kubectl apply -f -
```
You will see the following configurations for gateway and virtualservice. Look at the `hosts` parameters.

```
$ kubectl get gateway bookinfo-gateway -o yaml
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"networking.istio.io/v1alpha3","kind":"Gateway","metadata":{"annotations":{},"name":"bookinfo-gateway","namespace":"bookinfo"},"spec":{"selector":{"istio":"ingressgateway"},"servers":[{"hosts":["*"],"port":{"name":"http","number":80,"protocol":"HTTP"}}]}}
{"apiVersion":"networking.istio.io/v1alpha3","kind":"Gateway","metadata":{"annotations":{},"name":"bookinfo-gateway","namespace":"bookinfo1"},"spec":{"selector":{"istio":"ingressgateway"},"servers":[{"hosts":["bookinfo1.istio.apps.devday.ocpcloud.com"],"port":{"name":"http","number":80,"protocol":"HTTP"}}]}}
clusterName: ""
creationTimestamp: 2018-10-10T16:46:45Z
creationTimestamp: 2018-10-18T01:01:17Z
generation: 1
name: bookinfo-gateway
namespace: bookinfo
resourceVersion: "16011"
selfLink: /apis/networking.istio.io/v1alpha3/namespaces/bookinfo/gateways/bookinfo-gateway
uid: 12d4fddb-ccac-11e8-b16d-66d8cef31907
namespace: bookinfo1
resourceVersion: "4500380"
selfLink: /apis/networking.istio.io/v1alpha3/namespaces/bookinfo1/gateways/bookinfo-gateway
uid: 517d308a-d271-11e8-900a-069c4762f7ea
spec:
selector:
istio: ingressgateway
servers:
- hosts:
- '*'
- bookinfo1.istio.apps.devday.ocpcloud.com
port:
name: http
number: 80
protocol: HTTP
```

And the virtualservice would match the traffic at specific endpoints `/productpage`, ` /login`, `/logout` etc.

```
$ kubectl get virtualservice
NAME CREATED AT
bookinfo 6h
-----
$ kubectl get virtualservice bookinfo -o yaml
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"networking.istio.io/v1alpha3","kind":"VirtualService","metadata":{"annotations":{},"name":"bookinfo","namespace":"bookinfo"},"spec":{"gateways":["bookinfo-gateway"],"hosts":["*"],"http":[{"match":[{"uri":{"exact":"/productpage"}},{"uri":{"exact":"/login"}},{"uri":{"exact":"/logout"}},{"uri":{"prefix":"/api/v1/products"}}],"route":[{"destination":{"host":"productpage","port":{"number":9080}}}]}]}}
{"apiVersion":"networking.istio.io/v1alpha3","kind":"VirtualService","metadata":{"annotations":{},"name":"bookinfo","namespace":"bookinfo1"},"spec":{"gateways":["bookinfo-gateway"],"hosts":["bookinfo1.istio.apps.devday.ocpcloud.com"],"http":[{"match":[{"uri":{"exact":"/productpage"}},{"uri":{"exact":"/login"}},{"uri":{"exact":"/logout"}},{"uri":{"prefix":"/api/v1/products"}}],"route":[{"destination":{"host":"productpage","port":{"number":9080}}}]}]}}
clusterName: ""
creationTimestamp: 2018-10-10T16:46:45Z
creationTimestamp: 2018-10-18T01:01:17Z
generation: 1
name: bookinfo
namespace: bookinfo
resourceVersion: "16012"
selfLink: /apis/networking.istio.io/v1alpha3/namespaces/bookinfo/virtualservices/bookinfo
uid: 12e74346-ccac-11e8-b16d-66d8cef31907
namespace: bookinfo1
resourceVersion: "4500381"
selfLink: /apis/networking.istio.io/v1alpha3/namespaces/bookinfo1/virtualservices/bookinfo
uid: 51a76501-d271-11e8-900a-069c4762f7ea
spec:
gateways:
- bookinfo-gateway
hosts:
- '*'
- bookinfo1.istio.apps.devday.ocpcloud.com
http:
- match:
- uri:
Expand All @@ -197,19 +271,27 @@ spec:
host: productpage
port:
number: 9080
```

In order to access this application from outside the cluster you will use `bookinfo1.istio.apps.devday.ocpcloud.com`.

So how does the routing work?

We have a wildcard route exposed for `istio-ingressgateway` service on our openshift cluster. In my case it was `www.istio.apps.devday.ocpcloud.com` with `wildcardPolicy: Subdomain`. This means when we access any hostname `*.istio.apps.devday.ocpcloud.com`, it will be listened to by the `istio-ingressgateway` service. Based on the gateway and virtualservice configurations discussed above, the traffic will land in your application.

To summarize the routing:

`Client` --> `OpenShiftRouter`--> `istio-ingressgateway`-->`bookinfo-gateway`--> `bookinfo virtualservice`--> `productpage`

* OpenShift router receives the traffic for the default domain (in my case `*.apps.devday.ocpcloud.com`)
* Istio-ingressgateway service receives the traffic via wildcard route (in my case it is configured for `www.istio.apps.devday.ocpcloud.com` means it receives any `*.istio.apps.devday.ocpcloud.com`)
* `bookinfo-gateway` receives traffic for specific application hostname (in the above case `bookinfo1.istio.apps.devday.ocpcloud.com`)
* `bookinfo virtualservice` redirects the traffic to specific endpoints exposed by the application.

-----

The virtual service above shows that we can access product page at `/productpage` endpoint. This endpoint is for the Istio ingress i.e.,

```
$ kubectl get route -n istio-system istio-ingressgateway
NAME HOST/PORT PATH SERVICES PORT TERMINATION WILDCARD
istio-ingressgateway istio-ingressgateway-istio-system.192.168.64.72.nip.io istio-ingressgateway http2 None
```

> **Note** Your URLs would be different from mine. So use your values. If you want to know your URLs run `kubectl get route -n istio-system`
Expand Down Expand Up @@ -383,7 +465,7 @@ kubectl -n bookinfo delete pods --all # deletes all pods
In this chapter

* We have deployed our sample Bookinfo application and tested it
* Created a gateway to reach the application
* Created a gateway and virtualservice to reach the application.
* Added destination rules to set up routing rules later
* We also looked at how to monitor and trace this application using Istio's supported services

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